In general, a hydraulic excavator as a typical example of a construction machine comprises an automotive lower traveling structure, an upper revolving structure that is mounted on the lower traveling structure to be able to revolve thereon, and a working mechanism that is mounted at a front side of the upper revolving structure to be able to tilt thereto.
The upper revolving structure is provided with a revolving frame that forms a support structure, a floor member that is provided on the revolving frame and constitutes an operator's seat mounting section at the rear side and a foot rest section at the front side on which an operator rests its feet, an operator's seat that is mounted to the operator's seat mounting section of the floor member and on which an operator is seated, and right and left operating lever assemblies that are provided at both of the right and left sides of the operator's seat for operating the working mechanism.
An engine and various kinds of electric equipment such as illuminations, monitors, sensors and the like are mounted on the hydraulic excavator, and also a controller that controls these components is mounted thereon. As an arrangement location of the controller, there is known the construction where the controller is arranged on a support base in back of the operator's seat inside a cab box forming an operator's room (for example, see, Patent Document 1).